I’m anxious and frustrated

I seem to have been sold half a ticket

I bought and paid for tickets for 8 people to travel from Milan to Geneva, Switzerland. Once on the train in Italy the ticket inspector told us that we also needed an extra pass for Switzerland for which he charged us a further 456 Euro. I have no idea why and want to know why I was mis-sold the original tickets?

We also have to get home from here and don't want to have to pay again.
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